# Early Peri-Admission Lactate-to-Albumin (LAR), C-Reactive Protein-to-Albumin (CAR), and Procalcitonin-to-Albumin (PAR) Ratios and ICU Mortality in a Tertiary Cardiac ICU

## TL;DR

This study finds that certain blood ratios measured soon after ICU admission can predict mortality in critically ill patients, with lactate-to-albumin ratio being the most effective.

## Contribution

The study introduces and validates new composite ratios (LAR, CAR, PAR) as early predictors of ICU mortality in cardiac ICU patients.

## Key findings

- LAR and CAR, but not PAR, independently predicted ICU mortality after adjusting for age, sex, and admission category.
- LAR had the highest discrimination (AUC of 0.692) among the three ratios for predicting ICU mortality.
- High-risk subgroups were identified using cut-offs for LAR, CAR, and PAR, with LAR showing the strongest association with death.

## Abstract

Background/Objectives: Critically ill adults in intensive care units (ICUs) remain at high risk of death, while commonly used severity scores are complex and not always available at admission. We evaluated peri-admission lactate-to-albumin (LAR), C-reactive protein-to-albumin (CAR) and procalcitonin-to-albumin (PAR) ratios at ICU entry to predict ICU mortality in a cardiovascularly burdened cohort. Methods: We performed a single-centre retrospective observational cohort study in a tertiary cardiac ICU including adult admissions in 2024 with complete peri-admission lactate, C-reactive protein, procalcitonin and albumin. Results: Of 212 ICU admissions, 137 met the inclusion criteria. ICU mortality was 48.9%. Non-survivors had higher composite ratios and lower albumin than survivors. In multivariable models, LAR and CAR, but not PAR, remained independently associated with ICU mortality after adjustment for age, sex, and admission category. Receiver operating characteristic areas under the curve (AUC) were 0.692 for LAR, 0.677 for CAR and 0.625 for PAR. Cut-offs of LAR ≥ 0.106, CAR ≥ 3.18 and PAR ≥ 0.143 identified high-risk subgroups, with odds ratios for death of 6.18, 4.20 and 2.70, respectively, compared with lower-ratio patients, and LAR provided the best overall discrimination. Conclusions: Peri-admission LAR, CAR and PAR derived from routine tests in the ICU are associated with ICU mortality in critically ill adults, with LAR and CAR providing independent prognostic information and LAR showing the best discrimination. These simple composite ratios may complement severity scores for early risk stratification and warrant external validation.